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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Janusz Krzysztofik <jmkrzyszt@gmail.com>,
        Tony Lindgren <tony@atomide.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.16 169/279] ARM: OMAP1: ams-delta: fix deferred_fiq handler
Date:   Mon, 18 Jun 2018 10:12:34 +0200
Message-Id: <20180618080615.816817881@linuxfoundation.org>
In-Reply-To: <20180618080608.851973560@linuxfoundation.org>
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4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Janusz Krzysztofik <jmkrzyszt@gmail.com>

[ Upstream commit baf64250b4a513bf4ac226fd938692dc1836f4f6 ]

The deferred_fiq handler used to limit hardware operations to IRQ
unmask only, relying on gpio-omap assigned handler performing the ACKs.
Since commit 80ac93c27441 ("gpio: omap: Fix lost edge interrupts") this
is no longer the case as handle_edge_irq() has been replaced with
handle_simmple_irq() which doesn't touch the hardware.

Add single ACK operation per each active IRQ pin to the handler. While
being at it, move unmask operation out of irq_counter loop so it is
also called only once for each active IRQ pin.

Fixes: 80ac93c27441 ("gpio: omap: Fix lost edge interrupts")
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm/mach-omap1/ams-delta-fiq.c |   26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

--- a/arch/arm/mach-omap1/ams-delta-fiq.c
+++ b/arch/arm/mach-omap1/ams-delta-fiq.c
@@ -58,22 +58,24 @@ static irqreturn_t deferred_fiq(int irq,
 		irq_num = gpio_to_irq(gpio);
 		fiq_count = fiq_buffer[FIQ_CNT_INT_00 + gpio];
 
-		while (irq_counter[gpio] < fiq_count) {
-			if (gpio != AMS_DELTA_GPIO_PIN_KEYBRD_CLK) {
-				struct irq_data *d = irq_get_irq_data(irq_num);
+		if (irq_counter[gpio] < fiq_count &&
+				gpio != AMS_DELTA_GPIO_PIN_KEYBRD_CLK) {
+			struct irq_data *d = irq_get_irq_data(irq_num);
 
-				/*
-				 * It looks like handle_edge_irq() that
-				 * OMAP GPIO edge interrupts default to,
-				 * expects interrupt already unmasked.
-				 */
-				if (irq_chip && irq_chip->irq_unmask)
+			/*
+			 * handle_simple_irq() that OMAP GPIO edge
+			 * interrupts default to since commit 80ac93c27441
+			 * requires interrupt already acked and unmasked.
+			 */
+			if (irq_chip) {
+				if (irq_chip->irq_ack)
+					irq_chip->irq_ack(d);
+				if (irq_chip->irq_unmask)
 					irq_chip->irq_unmask(d);
 			}
-			generic_handle_irq(irq_num);
-
-			irq_counter[gpio]++;
 		}
+		for (; irq_counter[gpio] < fiq_count; irq_counter[gpio]++)
+			generic_handle_irq(irq_num);
 	}
 	return IRQ_HANDLED;
 }